Holographic Projection System Using Micro-Mirrors for Light Modulation

Abstract

The invention relates to a holographic projection system wherein light modulator means SLM with electromechanically moved micro-mirrors modulate a light wave front LWmod. According to the invention, a hologram processor HP sets micro-mirror surfaces of prior art spatial light modulator which are disposed as controllable diffraction gratings on a substrate of a control circuit, such that they reach a certain diffraction grating amplitude, by moving them continuously at right angles to the substrate, said diffraction grating amplitude being dependent on the content of a sequence of video holograms. The diffraction grating modulate a light wave which is emitted by the light modulator means and which generates illumination capable of generating interference according to a phase hologram, so that the modulated light wave is used directly for the holographic reconstruction.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a holographic projection system which contains light modulator means with individually controllable modulator cells in the form of electro-mechanically movable micro-mirrors, i.e. a so-called electro-mechanical system (MEMS), for modulating a light wave front. The modulator cells are illuminated by light capable of generating interference, and they are coded with sequences of video holograms in order to reconstruct holographically the optical appearance of three- dimensional scenes. The system shall be used predominantly to reconstruct a moving three-dimensional scene with holographic video means in real time or at least near real time. This makes particularly great demands on the resolution and speed of the light modulator means in order to be able to realise holographic reconstructions with high resolution, brightness and contrast while there is only little local and temporary cross-talking. Because in the micro-mechanic...

AI Technical Summary

Benefits of technology

[0021]It is the object of the present invention to find among the known light modulator means for modulating a light wave front with the help of discretely controllable modulator cells which have electromechanically movable micro-mirror surfaces those types which if used in a holographic projection system provide a high-quality holographic representation, in particular sufficient resolution and brightness if there is a rapidly changing sequence of video holograms of the moving three-dimensional scene. At the same time, the invention aims to identify the technical means which are necessary to take advantage of such light modulator means in a projection system for a high-quality holographic reconstruction, in particular in order to realise a high resolution and low noise while there is a rapidly changing sequence of video holograms.

[0028]The phase modulation behaviour of the above-mentioned diffraction grating light modulators is particularly well suited for the holographic reconstruction of three-dimensional scenes, because of the fast operating speed of the micro-mirrors and thanks to the fact that a great resolution can be realised inexpensively.

Problems solved by technology

A technical problem when realising such light modulators, however, are the fix micro-mirror surfaces of the controllable diffraction gratings, which are disposed between the moved micro-mirror surfaces.

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